The Perito Moreno Glacier is an active glacier. It is one of the few in the world and the only advancing in Patagonia, unlike others such as Upsala, which are becoming extinct.
This advance of approximately 100 meters per year is generating another phenomenon of shoking beauty: the breaking of the dam that forms in the brazo Rico of Lake Argentino, as with the advancing glacier, touch the opposite shore and forms a dam that stops the passage of water. Then the water seeps under the glacier and begins to undermine its base.
In 1917 occurred the first break. The process was repeated many times, at regular intervals that even have to fear for the demise of so prodigious show. Is that for the break occurs is necessary to comply with a series of steps that depend heavily on the action of both natural and other harmful changes made by the man on the environment.
Lake Argentino, water body in which lies the town of Perito Moreno Ice, has several arms. The one called Rico is behind the Magallanes Peninsula and flows into Lake Argentino by the Icebergs Canal. When the glacier advances and touches the coast of the peninsula forms a dam that prevents the arm Rico drain into the lake.
This arm continues receiving water and snow up to exceed the level of the lake by 8 or 10 meters and increasing pressure on the dam. For it to drop the water begins to seep through the areas where the glacier has ground contact. The passage of water erodes the base of the dam until the pressure is unbearable and that's when the fracture occurs as expected, which generates the unforgettable phenomenon.
One of the latest breakdowns was in 1988 and when the people feared for his disappearance happened again with unexpected frequency in March 2004 and 2006. Experts say it is not possible to predict such an event.
There are reasons to be attentive to the work of ice in the Perito Moreno. Each fracture is unique and unrepeatable. And while it is difficult to predict what will happen in the coming years, we expect that to happen again, to once again enjoy the beautiful spectacle of this giant in Patagonia.
Another memorable break was in 2008 occured in winter. Was an unusual event because these phenomena are common in summer.
From the Secretariat of Tourism of Santa Cruz have clarified some mistakes made in talking about the mythical Perito Moreno. One of them has to do with the size of the colossus. The truth is that the Perito Moreno has a length of 30 km, an area of 257 km2 and a height ranging from 50 to 70 meters above the lake level.
And another is related to the idea that spreads about "the breaking of the Perito Moreno glacier occurs cyclically every four years." The historical evidence shows that the first openness was in 1917 without specifying the time of the year, in 1926 the geologist and founder of the paleontological museum in Trelew, Egidio Feruglio, spoke of an openness to "allow the passage of a small boat" , in February 1940 rupture of the glacier front occured and then in 1942, 1947, 1949, June / July 1951, March 1952, March 1953, 1956 and then a big break until 1966.
Then, the frequency is even more variable: 1970, 1972, 1975, 1977, 1980, 1984 and 1988. From then on, a long silence that was broken in 2004, two years later in 2006 and the last in 2008.